The gas ethyne, commonly known as acetylene, has the chemical formula C$2$H$2$ and is commonly used in welding. In combination with oxygen, ethyne burns according to the following equation, where a$,$ b$,$ c and d are integers.

aC$2$H$2+$ bO$2$ cCO$2+$ dH$2$O

First balance the equation by finding suitable values of a$,$ b$,$ c and d$,$ then calculate the mass of oxygen required for the complete combustion of $950$g of ethyne.

The following atomic masses may be useful: H $=1\mathrm{.}0,$ C $=12\mathrm{.}0,$ O $=16\mathrm{.}0.$